Portable modem



FIG. 1 is a left side elevational view;

FIG. 2 is a front elevational view;

FIG. 3 is a right side elevational view;

FIG. 4 is a top plan view; and,

FIG. 5 is a bottom plan view.

The rear of the article is plain and unornamented.

The ornamental design for a portable modem, as shown and described.